Johnson Matthey Converter Model - Case Study
The development and use of a general
model for studying and predicting the distribution of elements in the
high temperature processing of precious metals.
metal containing substrates for catalytic converters used in the cars
Johnson Matthey is a world leader in the
production of catalysts, precious metals and speciality chemicals. The
very nature of these products means that the ability to optimise the
recovery of precious metals from scrap or ore is highly desirable.
For a number of years scientists at Johnson
Matthey Technology Centre, in collaboration with Anglo American
Platinum, have used software tools and thermodynamic databases from the
National Physical Laboratory in order to gain a more fundamental
understanding of key production processes. However recently it has
become possible to use the NPL thermodynamic and phase diagram
software, MTDATA, in a new and exciting way.
During a year-long training secondment at NPL, JM
scientist Dr Hudai Kara developed a general modelling framework based
on the programming interface to MTDATA. The use of MTDATA provides a
rigorous and reliable way to determine the partitioning of elements
between phases. Now with the addition of process specific modelling
this becomes an even move powerful tool.
A readily adaptable general "converter" model has
been developed to study aspects of the production of precious metal
from sulphide ores, on behalf of Anglo American Platinum, and also the
recycling of precious metal scrap. Although superficially these two
processes appear very different they both involve the injection of
oxygen into a high temperature liquid and both result in the creation
of a liquid oxide phase in addition to the original liquid holding the
precious metal. The real problem is how to control the removal of
unwanted elements from the valuable phase without losing any value into
the waste oxide. A small deviation in the composition or loss of a
precious metal such as rhodium can have great economic importance.
the converter simulation program
This screen shot shows Dr Kara's model is able to
follow the formation of oxide and gas phases as oxygen injection
proceeds and also track the composition of the original liquid phase.
In addition to gaining a deeper understanding at the research centre
this also opens up the possibility of taking this type of modelling
directly into the plant environment and hence providing plant
management and even operators with virtual real-time and ahead-of-time
prediction to supplement the on-plant measurements.
The ability to quickly model processes of
considerable complexity, where many elements are distributed between
various high temperature liquid, solid and gas phases, gives JM and
Anglo American Platinum a significant advantage in tackling the many
challenges the modern high temperature materials processor faces. These
range from problems specific to the precious metal industry where very
close control over materials and continual sensitivity to ever changing
metal prices are required to general issues such as coping with a
variable feedstock, optimising the energy usage and controlling waste
A key aspect of this work was the ability to use
an extremely high quality and extensive database of oxide thermodynamic
data. This database has been developed at NPL over a number of years
via the sponsorship of an industrial consortium, of which JM and Anglo
American Platinum are members, coordinated by the Mineral Industry
Research Organisation. The DTI MPP Programme supported other aspects of
this work at NPL.
Further details of MTDATA, the NPL Oxide
Thermodynamic Database and their use in modelling real industrial
processes can be obtained by contacting Hugh Davies